feat: auto limit string if truncate is set (#428)

Author: OlivierDehaene

core/src/tokenization.rs

@@ -274,7 +274,7 @@ fn prepare_pre_prompt(
 
 #[allow(clippy::too_many_arguments)]
 fn tokenize_input(
-    inputs: EncodingInput,
+    mut inputs: EncodingInput,
     add_special_tokens: bool,
     max_input_length: usize,
     truncate_params: Option<TruncationParams>,
@@ -288,9 +288,12 @@ fn tokenize_input(
     let input_chars = inputs.count_chars();
     let limit = max_input_length * MAX_CHAR_MULTIPLIER;
     if input_chars > limit {
-        return Err(TextEmbeddingsError::Validation(format!(
-            "`inputs` must have less than {limit} characters. Given: {input_chars}"
-        )));
+        if truncate_params.is_none() {
+            return Err(TextEmbeddingsError::Validation(format!(
+                "`inputs` must have less than {limit} characters. Given: {input_chars}"
+            )));
+        }
+        inputs.apply_limit(limit);
     }
 
     let encoding = match inputs {
@@ -426,6 +429,25 @@ impl EncodingInput {
             EncodingInput::Ids(v) => v.len(),
         }
     }
+
+    fn apply_limit(&mut self, limit: usize) {
+        let truncate_string = |s: &mut String, limit: usize| {
+            if s.is_char_boundary(limit) {
+                s.truncate(limit)
+            }
+        };
+
+        match self {
+            EncodingInput::Single(s) => {
+                truncate_string(s, limit);
+            }
+            EncodingInput::Dual(s1, s2) => {
+                truncate_string(s1, limit / 2);
+                truncate_string(s2, limit / 2);
+            }
+            EncodingInput::Ids(_) => {}
+        }
+    }
 }
 
 impl From<String> for EncodingInput {